Perspectives on sustainable process control optimization through reusability of non-regenerated Fenton sludge in landfill leachate treatment

Abstract

The production of iron-rich waste (Fenton sludge) and the high chemical dosage required in the Fenton-based advanced oxidation process (AOP) harm the environment, making disposal challenges and the technique unsustainable. Thus, finding adequate Fenton sludge (FS) reuse alternatives is critical to addressing the Fenton process's drawbacks in addition to environmental protection. This study signifies that FS could be employed satisfactorily without requiring costly regeneration operations or chemical dosages, such as landfill leachate, during wastewater treatment. In this study, two sets of experiments were carried out utilizing the most often used optimization tools: design of experiments (DOE) (central composite design (CCD)/response surface methodology (RSM). Under optimized conditions, reasonably high chemical oxygen demand (COD) removal of 62 %, total suspended solids (TSS) removal of >95 %, and colour removal of >80 % was obtained after 48 min of reaction time with 84 mL/L sludge reused at pH 3.6. The method's key influencing factors were sludge volume, pH, and reaction time. Furthermore, reused FS exhibited lower toxicity and total volatile solids, indicating that sludge reuse is superior to direct disposal. According to the techno-economic analysis, using non-regenerated sludge as proposed reduces toxic iron-based waste and total wastewater treatment costs.